A variety of pulse sequences have been described for converting nuclear spin magnetisation into long-lived singlet order for nuclear spin-1/2 pairs.

Nuclear spin singlet states are often found to allow long-lived storage of nuclear magnetization, which can form the basis of novel applications in spectroscopy, imaging, and in studies of dynamic...

A range of nuclear magnetic resonance spectroscopy and imaging applications are limited by the short lifetimes of magnetization in solution. Long-lived states, which are slowly relaxing configurations of nuclear spins, have been shown to alleviate this limitation. Long-lived states have decay lifetimes T LLS significantly exceeding the longitudinal relaxation time T 1 , in some cases by an order of magnitude. Here we present an experimental case of a long-lived state for a 15 N labelled molecular system in solution. We observe a strongly biexponential decay for the long-lived state, with the lifetime of the slowly relaxing component exceeding 40 minutes, ∼21 times longer than the spin-lattice relaxation time T 1. The lifetime of the long-lived state was revealed by using a dedicated two-field NMR spectrometer capable of fast sample shuttling between high and low magnetic fields, and the application of a resonant radiofrequency field at low magnetic field. The relaxation characteristics of the long-lived state are examined.

Synthesis of Kr@C60 is achieved by quantitative high-pressure encapsulation of the noble gas into an open-fullerene, and subsequent cage closure. Krypton is the largest noble gas entrapped in C60 using...

Some nuclear spin systems support long-lived states, which display greatly extended relaxation times relative to the relaxation time of nuclear spin magnetization. In spin-1/2 pairs, the such a long-lived state is given by singlet order, representing the difference of the population of the nuclear singlet state and the mean population of the three triplets. In many cases, the experiments with long-lived singlet order are very time-consuming because of the need to wait for singlet order decay before the experiment can be repeated; otherwise spin order remaining from a previous measurement may lead to experimental artefacts. Here we propose techniques for fast and efficient singlet order destruction. These methods exploit coherent singlet-triplet conversion; in some cases, multiple conversion steps are introduced. We demonstrate that singlet order destruction enables a dramatic reduction of the waiting time between consecutive experiments and suggest to use this approach in singlet-state NMR experiments with nearly equivalent spins.